Seismic signatures of volcanic eruptions
Abstract/Contents
- Abstract
- Increases in seismic wave radiation coincident with explosive volcanic eruptions demonstrate that eruptive processes exert forces on the surrounding earth, exciting seismic waves. Studies of seismic radiation from volcanoes have been done to gain insight into internal dynamics that cannot be directly observed. However, traditional seismogram interpretation is nonunique and often ambiguously related to eruptive processes, which limits the amount of information we can learn from the seismic signal. In this dissertation, I develop a theoretical framework to rigorously connect internal fluid dynamics to associated seismic radiation in order to calculate synthetic seismograms from simulated eruptions. Based on this theoretical work, I present the procedure to translate wall shear traction and pressure changes into force and moment histories, which are then convolved with numerical Green's functions to calculate seismograms. This is referenced as the synthetic seismogram calculation workflow. This process allows for direct connection between an eruptive process and its seismic signature. This workflow is one of the first instances of using unsteady conduit flow models to quantitatively study seismicity. I then apply this workflow in the study of potential sources of commonly observed types of seismic signals at volcanic eruptions: very-long-period (VLP) waveforms and incoherent eruptive tremor. I demonstrate that rupture of a magmatic plug and fragmentation of high viscosity magma yield distinct signatures in the VLP frequency band with coincident modulations in mass eruption rate, providing observationally testable predictions. I explore an existing model for eruptive tremor based on particle impacts and turbulence in the upper conduit using steady-state conduit flow models and more rigorous treatment of wave propagation, finding extreme parameter values are required to match observed tremor amplitudes. I present a study of a potential alternative mechanism for eruption tremor due to fluctuating fragmentation, finding that stochastic fluctuations in fragmentation arising from advection of heterogeneous magma yield stochastic seismic signals.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2024; ©2024 |
| Publication date | 2024; 2024 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Coppess, Katherine Rowe |
|---|---|
| Degree supervisor | Burchat, Patricia |
| Degree supervisor | Dunham, Eric |
| Thesis advisor | Burchat, Patricia |
| Thesis advisor | Dunham, Eric |
| Thesis advisor | Pamukcu, Ayla Susan |
| Thesis advisor | Segall, Paul, 1954- |
| Degree committee member | Pamukcu, Ayla Susan |
| Degree committee member | Segall, Paul, 1954- |
| Associated with | Stanford University, School of Humanities and Sciences |
| Associated with | Stanford University, Department of Physics |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Katherine R. Coppess. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis Ph.D. Stanford University 2024. |
| Location | https://purl.stanford.edu/bh294yb5215 |
Access conditions
- Copyright
- © 2024 by Katherine Rowe Coppess
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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